Magnetic tunnel junctions

ABSTRACT

A magnetic tunnel junction comprises a conductive first magnetic electrode comprising magnetic recording material, a conductive second magnetic electrode spaced from the first electrode and comprising magnetic reference material, and a non-magnetic tunnel insulator material between the first and second electrodes. The magnetic reference material of the second electrode comprises a synthetic antiferromagnetic construction comprising two spaced magnetic regions one of which is closer to the tunnel insulator material than is the other. The one magnetic region comprises a polarizer region comprising Co x Fe y B z  where “x” is from 0 to 90, “y” is from 10 to 90, and “z” is from 10 to 50. The Co x Fe y B z  is directly against the tunnel insulator. A non-magnetic region comprising an Os-containing material is between the two spaced magnetic regions. The other magnetic region comprises a magnetic Co-containing material. Other embodiments are disclosed.

TECHNICAL FIELD

Embodiments disclosed herein pertain to magnetic tunnel junctions.

BACKGROUND

A magnetic tunnel junction is an integrated circuit component having twoconductive magnetic electrodes separated by a thin non-magnetic tunnelinsulator material (e.g., dielectric material). The insulator materialis sufficiently thin such that electrons can tunnel from one magneticelectrode to the other through the insulator material under appropriateconditions. At least one of the magnetic electrodes can have its overallmagnetization direction switched between two states at a normaloperating write or erase current/voltage, and is commonly referred to asthe “free” or “recording” electrode. The other magnetic electrode iscommonly referred to as the “reference”, “fixed”, or “pinned” electrode,and whose overall magnetization direction will not switch uponapplication of the normal operating write or erase current/voltage. Thereference electrode and the recording electrode are electrically coupledto respective conductive nodes. Electrical resistance between those twonodes through the reference electrode, insulator material, and therecording electrode is dependent upon the magnetization direction of therecording electrode relative to that of the reference electrode.Accordingly, a magnetic tunnel junction can be programmed into one of atleast two states, and those states can be sensed by measuring currentflow through the magnetic tunnel junction. Since magnetic tunneljunctions can be “programmed” between two current-conducting states,they have been proposed for use in memory integrated circuitry.Additionally, magnetic tunnel junctions may be used in logic or othercircuitry apart from or in addition to memory.

The overall magnetization direction of the recording electrode can beswitched by a current-induced external magnetic field or by using aspin-polarized current to result in a spin-transfer torque (STT) effect.Charge carriers (such as electrons) have a property known as “spin”which is a small quantity of angular momentum intrinsic to the carrier.An electric current is generally unpolarized (having about 50% “spin-up”and about 50% “spin-down” electrons). A spin-polarized current is onewith significantly more electrons of either spin. By passing a currentthrough certain magnetic material (sometimes also referred to aspolarizer material), one can produce a spin-polarized current. If aspin-polarized current is directed into a magnetic material, spinangular momentum can be transferred to that material, thereby affectingits magnetization orientation. This can be used to excite magnetizationprecession or even flip (i.e., switch) the orientation/domain directionof the magnetic material if the spin-polarized current is of sufficientmagnitude.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagrammatic sectional view of a substrate fragmentcomprising a magnetic tunnel junction in accordance with an embodimentof the invention.

FIG. 2 is a diagrammatic sectional view of a substrate fragmentcomprising a magnetic tunnel junction in accordance with an embodimentof the invention.

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS

Embodiments of the invention encompass magnetic tunnel junctions.Example embodiments are initially described with reference to FIG. 1with respect to a substrate fragment 10, and which may comprise asemiconductor substrate. In the context of this document, the term“semiconductor substrate” or “semiconductive substrate” is defined tomean any construction comprising semiconductive material, including, butnot limited to, bulk semiconductive materials such as a semiconductivewafer (either alone or in assemblies comprising other materialsthereon), and semiconductive material layers (either alone or inassemblies comprising other materials). The term “substrate” refers toany supporting structure, including, but not limited to, thesemiconductive substrates described above. Substrate fragment 10comprises a base or substrate 11 showing various materials having beenformed as an elevational stack there-over. Materials may be aside,elevationally inward, or elevationally outward of the FIG. 1-depictedmaterials. For example, other partially or wholly fabricated componentsof integrated circuitry may be provided somewhere about or withinfragment 10. Substrate 11 may comprise any one or more of conductive(i.e., electrically herein), semiconductive, or insulative/insulator(i.e., electrically herein) materials. Regardless, any of the materials,regions, and structures described herein may be homogenous ornon-homogenous, and regardless may be continuous or discontinuous overany material which such overlie. Further, unless otherwise stated, eachmaterial may be formed using any suitable or yet-to-be-developedtechnique, with atomic layer deposition, chemical vapor deposition,physical vapor deposition, epitaxial growth, diffusion doping, and ionimplanting being examples.

A magnetic tunnel junction 15 is over substrate 11, and comprises aconductive first magnetic (i.e., ferrimagnetic or ferromagnetic herein)electrode 25 comprising magnetic recording material and a conductivesecond magnetic electrode 27 spaced from first electrode 25 andcomprising magnetic reference material. A non-magnetic tunnel insulatormaterial 22 (e.g., comprising, consisting essentially of, or consistingof MgO) is between the first and second electrodes. Electrodes 25 and 27individually may contain non-magnetic insulator, semiconductive, and/orconductive material or regions. However, electrodes 25 and 27 whenconsidered individually are characterized as being overall andcollectively magnetic and conductive even though the electrode may haveone or more regions therein that are intrinsically locally non-magneticand/or non-conductive. Further, reference to “magnetic” herein does notrequire a stated magnetic material or region to be magnetic as initiallyformed, but does require some portion of the stated magnetic material orregion to be functionally “magnetic” in a finished circuit constructionof the magnetic tunnel junction.

Example thickness ranges for each of components 25 and 27 is about 20Angstroms to about 250 Angstroms, and for component 22 about 5 Angstromsto about 50 Angstroms. An ideal thickness for component 27 is about 110Angstroms. In this document, “thickness” by itself (no precedingdirectional adjective) is defined as the mean straight-line distancethrough a given material or region perpendicularly from a closestsurface of an immediately adjacent material of different composition orof an immediately adjacent region. Additionally, the various materialsand regions described herein may be of substantially constant thicknessor of variable thicknesses. If of variable thickness, thickness refersto average thickness unless otherwise indicated. As used herein,“different composition” only requires those portions of two statedmaterials or regions that may be directly against one another to bechemically and/or physically different, for example if such materials orregions are not homogenous. If the two stated materials or regions arenot directly against one another, “different composition” only requiresthat those portions of the two stated materials or regions that areclosest to one another be chemically and/or physically different if suchmaterials or regions are not homogenous. In this document, a material,region, or structure is “directly against” another when there is atleast some physical touching contact of the stated materials, regions,or structures relative one another. In contrast, “over”, “on”, and“against” not preceded by “directly” encompass “directly against” aswell as construction where intervening material(s), region(s), orstructure(s) result(s) in no physical touching contact of the statedmaterials, regions, or structures relative one another.

The elevational positions of electrodes 25 and 27 may be reversed and/oran orientation other than an elevational stack may be used (e.g.,lateral; diagonal; a combination of one or more of elevational,horizontal, diagonal; etc.). In this document, “elevational”, “upper”,“lower”, “top”, and “bottom” are with reference to the verticaldirection. “Horizontal” refers to a general direction along a primarysurface relative to which the substrate is processed during fabrication,and vertical is a direction generally orthogonal thereto. Further,“vertical” and “horizontal” as used herein are generally perpendiculardirections relative one another and independent of orientation of thesubstrate in three-dimensional space.

The magnetic reference material of second conductive magnetic electrode27 comprises a synthetic antiferromagnetic construction 23 thatcomprises two spaced magnetic regions 26 and 28 one of which (26) iscloser to tunnel insulator material 22 than is the other (28). The onemagnetic region comprises a polarizer region 30 comprisingCo_(x)Fe_(y)B_(z) where “x” is from 0 to 90, “y” is from 10 to 90, and“z” is from 10 to 50 (i.e., x+y+z totaling 100). Polarizer region 30 maycomprise, consist essentially of, or consist of such Co_(x)Fe_(y)B_(z).Regardless, Co_(x)Fe_(y)B_(z) thereof is directly against tunnelinsulator 22. In one embodiment, “x” is zero and in another embodiment“x” is greater than zero. Example thickness ranges for theCo_(x)Fe_(y)B_(z) are 5 Angstroms to 20 Angstroms and 5 Angstroms to 15Angstroms, with 7 Angstroms being one ideal example.

At least one of elemental W, elemental Mo, elemental Fe,Co_(a)Fe_(b)W_(c), Co_(a)Fe_(b)Mo_(c), and Co_(a)Fe_(b)Ta_(c) isdirectly against the Co_(x)Fe_(y)B_(z), where “a” is from 0 to 50, “b”is from 50 to 99, and “c” is from 1 to 50 (i.e., a+b+c totaling 100).Such is shown as a region 32 which may comprise, consist essentially of,or consist of one or more of such materials. In one embodiment, suchmaterial of region 32 that is directly against the Co_(x)Fe_(y)B_(z) iselemental W, in one embodiment is elemental Mo, in one embodiment iselemental Fe, in one embodiment is Co_(a)Fe_(b)W_(c), in one embodimentis Co_(a)Fe_(b)Mo_(c), or in one embodiment is Co_(a)Fe_(b)Ta_(c). Inone embodiment, the material of region 32 that is directly against theCo_(x)Fe_(y)B_(z) comprises a mixture or alloy of at least two ofelemental W, elemental Mo, elemental Fe, Co_(a)Fe_(b)W_(c),Co_(a)Fe_(b)Mo_(c), and Co_(a)Fe_(b)Ta_(c), and in one embodimentcomprises a mixture or alloy of at least three of such compositions.Example thickness ranges for region 32 are 1 Angstrom to 10 Angstromsand 2 Angstroms to 5 Angstroms, with 2 Angstroms being one idealexample.

Magnetic Co_(g)Fe_(h)B_(i) of a region 34 is directly against the atleast one of elemental W, elemental Mo, elemental Fe, Co_(a)Fe_(b)W_(c),Co_(a)Fe_(b)Mo_(c), and Co_(a)Fe_(b)Ta_(c), where “g” is from 0 to 100,“h” is from 0 to 90, and “i” is from 0 to 50 (i.e., g+h+i totaling 100),with at least one of “g” and “h” being greater than zero. Examplethickness ranges for the Co_(g)Fe_(h)B_(i) are 5 Angstroms to 30Angstroms and 10 Angstroms to 20 Angstroms, with 7 Angstroms being oneideal example. Region 34 may comprise, consist essentially of, orconsist of Co_(g)Fe_(h)B_(i).

A non-magnetic region 36 comprising at least one of Ir-containingmaterial, Ru-containing material, Rh-containing material, andOs-containing material is between spaced magnetic regions 26 and 28.Such materials may comprise one or more dopants and/or other materialsin combination with the Ru, Rh, and/or Os. Such dopants and/or othermaterials may tailor chemical and/or physical properties of region 36for particular applications. The at least one of Ir-containing material,Ru-containing material, Rh-containing material, and Os-containingmaterial is directly against cobalt-containing material as describedbelow. In one embodiment, the at least one of Ir-containing material,Ru-containing material, Rh-containing material, and Os-containingmaterial are at least one of elemental Ir, elemental Ru, elemental Rh,and elemental Os, respectively. In one embodiment, the at least one ofIr-containing material, Ru-containing material, Rh-containing material,and Os-containing material are a mixture or alloy of at least two ofelemental Ir, elemental Ru, elemental Rh, and elemental Os, and in oneembodiment a mixture or alloy of at least three of elemental Ir,elemental Ru, elemental Rh, and elemental Os. Example thickness rangesfor the at least one of Ir-containing material, Ru-containing material,Rh-containing material, and Os-containing material (e.g., region 36) are2 Angstroms to 10 Angstroms and 5 Angstroms to 7 Angstroms, with 7Angstroms being one ideal example. Regardless, non-magnetic region 36may comprise, consist essentially of, or consist of one or more of suchmaterials.

Other magnetic region 28 comprises a magnetic Co-containing material 38directly against the at least one of Ir-containing material,Ru-containing material, Rh-containing material, and Os-containingmaterial of region 36. Co-containing material 38 may comprise one ormore dopants and/or other materials in combination with the Co. Suchdopants and/or other materials may tailor chemical and/or physicalproperties of region 36 for particular applications. In one embodiment,magnetic Co-containing material 38 is elemental Co. Example thicknessranges for Co-containing material 38 are 5 Angstroms to 30 Angstroms and10 Angstroms to 20 Angstroms, with 14 Angstroms being one ideal example.Region 28 may comprise, consist essentially of, or consist ofCo-containing material.

In one embodiment, second electrode 27 comprises a non-magnetic region40 comprising at least one of non-magnetic elemental Ir, non-magneticelemental Pt, and non-magnetic elemental Ru that is directly againstmagnetic Co-containing material 38. Co-containing material 38 is betweena) the at least one of Ir-containing material, Ru-containing material,Rh-containing material, and Os-containing material of region 36 and b)the at least one of non-magnetic elemental Ir, non-magnetic elementalPt, and non-magnetic elemental Ru of region 40. In one embodiment, theat least one of non-magnetic elemental Ir, non-magnetic elemental Pt,and non-magnetic elemental Ru comprises a mixture or alloy of at leasttwo of elemental Ir, elemental Pt, and elemental Ru, and in oneembodiment a mixture or alloy of at least three of elemental Ir,elemental Pt, and elemental Ru. Example thickness ranges for the atleast one of elemental Ir, elemental Pt, and elemental Ru (e.g., region40) are 0 Angstroms to 100 Angstroms, 5 Angstroms to 100 Angstroms, and5 Angstroms to 50 Angstroms, with 50 Angstroms being one ideal example.Regardless, non-magnetic region 40 may comprise, consist essentially of,or consist of one or more of such materials.

In one embodiment, second electrode 27 comprises non-magneticNi_(s)Fe_(t)Cr_(u) of a non-magnetic region 42 directly against the atleast one of non-magnetic elemental Ir, non-magnetic elemental Pt, andnon-magnetic elemental Ru of region 40, where “s” is from 50 to 100, “t”is from 0 to 30, and “u” is from 0 to 45 (i.e., s+t+u totaling 100).Region 40 is between magnetic Co-containing material 38 and non-magneticNi_(s)Fe_(t)Cr_(u). 42. Example thickness ranges for Ni_(s)Fe_(t)Cr_(u)42 are 0 Angstroms to 60 Angstroms, 5 Angstroms to 60 Angstroms, and 10Angstroms to 40 Angstroms, with 30 Angstroms being one ideal example.Regardless, region 42 may comprise, consist essentially of, or consistof Ni_(s)Fe_(t)Cr_(u).

In one embodiment, conductive first magnetic electrode 25 comprisesnon-magnetic conductive material 44 and magnetic recording material 46.Non-magnetic conductive material 44 may be any suitable conductivematerial(s) such as elemental metals, an alloy or mixture of elementalmetals, conductive metal compounds, and conductively doped semiconductormaterial, with Ru being but one example. An example thickness range formaterial 44 is 10 to 500 Angstroms. In one embodiment, dielectricmaterial 48 is between non-magnetic conductive material 44 and magneticrecording material 46 (in one embodiment directly against at least oneand in one embodiment directly against both), and magnetic recordingmaterial 46 is between dielectric material 48 and tunnel insulator 22.In one embodiment, first magnetic electrode 25 is devoid of any magneticpolarizer region between dielectric material 48 and non-magneticconductive material 44. In one embodiment, tunnel insulator 22 anddielectric material 48 are the same composition, and which in oneembodiment is MgO. Example thickness ranges for dielectric material 48are 5 Angstroms to 50 Angstroms, 5 Angstroms to 20 Angstroms, and 5Angstroms to 15 Angstroms, with 15 Angstroms being one ideal example. Inone embodiment, dielectric material 48 has a smaller thickness than thatof tunnel insulator 22. Example thickness ranges for magnetic recordingmaterial 46 are 5 Angstroms to 50 Angstroms and 5 Angstroms to 20Angstroms, with 13 Angstroms being one ideal example.

In one embodiment, magnetic recording material 46 comprises an alloy 50comprising Co, Fe, and B, and comprises Fe 52 directly against alloy 50.In one embodiment, alloy 50 is directly against tunnel insulator 22.Example ideal thicknesses for alloy 50 and Fe 52 are 10 Angstroms and 3Angstroms, respectively.

Ideally the materials and regions of first electrode 25 and secondelectrode 27 are crystalline (e.g., ideally all BCC 001) although suchmay be amorphous or include amorphous material and regions.Characterization of a material or region as being “crystalline” whereused in this document requires at least 90% by volume of the statedmaterial or region to be crystalline. Characterization of a material orregion as being “amorphous” where used in this document requires atleast 90% by volume of the stated material to be amorphous.

Another example embodiment magnetic tunnel junction 15 a is shown withrespect to a substrate fragment 10 a in FIG. 2. Like numerals from theabove-described embodiments have been used where appropriate, with someconstruction differences being indicated with the suffix “a”. Syntheticantiferromagnetic construction 23 a of the magnetic reference materialof second electrode 27 a comprises two spaced magnetic regions 26 a and28 one of which (26 a) is closer to tunnel insulator material 22 than isthe other (28). Again, the one magnetic region comprises polarizerregion 30 comprising the Co_(x)Fe_(y)B_(z) referred to above that isdirectly against tunnel insulator 22. In one ideal example, theCo_(x)Fe_(y)B_(z) of polarizer region 30 is 10 Angstroms in thickness.Non-magnetic region 36 is between magnetic regions 26 a and 28 (incertain embodiments directly against at least one or both of regions 26a and 28) and comprises an Os-containing material. Non-magnetic region36 may comprise, consist essentially of, or consist of Os-containingmaterial. In one embodiment, the Os-containing material is elemental Os.Any other attribute(s) or aspect(s) as described above and/or shown inFIG. 1 may be used in the FIG. 2 embodiments.

The example embodiments of FIGS. 1 and 2 depict single magnetic tunneljunctions (SMTJs). However, dual magnetic tunnel junctions (DMTJs) ormore than dual (two) magnetic tunnel junctions are contemplated (i.e.,having at least two tunnel insulator regions and a respective polarizerregion proximate thereto).

The magnetic tunnel junctions discussed above may be utilized in memoryproducts or specific memory technologies (e.g., MRAM. STT-MRAM, etc.),or in other technologies (e.g., logic, sensors, oscillators, etc.). Themagnetic tunnel junctions may be incorporated into electronic systems.Such electronic systems may be used in, for example, memory modules,device drivers, power modules, communication modems, processor modules,and application-specific modules, and may include multilayer, multichipmodules. The electronic systems may be any of a broad range of systems,such as, for example, cameras, wireless devices, displays, chip sets,set top boxes, games, lighting, vehicles, clocks, televisions, cellphones, personal computers, automobiles, industrial control systems,aircraft, etc.

CONCLUSION

In some embodiments, a magnetic tunnel junction comprises a conductivefirst magnetic electrode comprising magnetic recording material, aconductive second magnetic electrode spaced from the first electrode andcomprising magnetic reference material, and a non-magnetic tunnelinsulator material between the first and second electrodes. The magneticreference material of the second electrode comprises a syntheticantiferromagnetic construction comprising two spaced magnetic regionsone of which is closer to the tunnel insulator material than is theother. The one magnetic region comprises a polarizer region comprisingCo_(x)Fe_(y)B_(z) where “x” is from 0 to 90, “y” is from 10 to 90, and“z” is from 10 to 50. The Co_(x)Fe_(y)B_(z) is directly against thetunnel insulator. At least one of elemental W, elemental Mo, elementalFe, Co_(a)Fe_(b)W_(c), Co_(a)Fe_(b)Mo_(c), and Co_(a)Fe_(b)Ta_(c) isdirectly against the Co_(x)Fe_(y)B_(z), where “a” is from 0 to 50, “b”is from 50 to 99, and “c” is from 1 to 50. Magnetic Co_(g)Fe_(h)B_(i) isdirectly against the at least one of elemental W, elemental Mo,elemental Fe, Co_(a)Fe_(b)W_(c), Co_(a)Fe_(b)Mo_(c), andCo_(a)Fe_(b)Ta_(c), where “g” is from 0 to 100, “h” is from 0 to 90, and“i” is from 0 to 50, with at least one of “g” and “h” being greater thanzero. A non-magnetic region comprising at least one of Ir-containingmaterial, Ru-containing material, Rh-containing material, andOs-containing material is between the two spaced magnetic regions. Theat least one of Ir-containing material, Ru-containing material,Rh-containing material, and Os-containing material is directly againstthe elemental Co. The other magnetic region comprises a magneticCo-containing material directly against the at least one ofIr-containing material, Ru-containing material, Rh-containing material,and Os-containing material.

In some embodiments, a magnetic tunnel junction comprises a conductivefirst magnetic electrode comprising magnetic recording materialcomprising 3 Angstroms thick Fe directly against an alloy comprising Co,Fe, and B that is 10 Angstroms thick. A conductive second magneticelectrode is spaced from the first electrode and comprises magneticreference material. A non-magnetic tunnel insulator material is betweenthe first and second electrodes. The first magnetic electrode comprisesdielectric material directly against the Fe. The alloy comprising Co,Fe, and B is directly against the tunnel insulator. The first magneticelectrode comprises non-magnetic conductive material that is directlyagainst the dielectric material. The first magnetic electrode is devoidof any magnetic polarizer region between the dielectric material and thenon-magnetic conductive material. The magnetic reference material of thesecond electrode comprises a synthetic antiferromagnetic constructioncomprising two spaced magnetic regions one of which is closer to thetunnel insulator material than is the other. The one magnetic regioncomprises a 7 Angstroms thick polarizer region comprisingCo_(x)Fe_(y)B_(z) where “x” is from 0 to 90, “y” is from 10 to 90, and“z” is from 10 to 50. The Co_(x)Fe_(y)B_(z) is directly against thetunnel insulator. A 2 Angstroms thick region of at least one ofelemental W, elemental Mo, elemental Fe, Co_(a)Fe_(b)W_(c),Co_(a)Fe_(b)Mo_(c), and Co_(a)Fe_(b)Ta_(c) is directly against theCo_(x)Fe_(y)B_(z), where “a” is from 0 to 50, “b” is from 50 to 99, and“c” is from 1 to 50. Seven Angstroms of magnetic Co_(g)Fe_(h)B_(i) isdirectly against the at least one of elemental W, elemental Mo,elemental Fe, Co_(a)Fe_(b)W_(c), Co_(a)Fe_(b)Mo_(c), andCo_(a)Fe_(b)Ta_(c), where “g” is from 0 to 100, “h” is from 0 to 90, and“i” is from 0 to 50 with at least one of “g” and “h” being greater thanzero. A 7 Angstroms thick non-magnetic region comprising at least one ofIr-containing material, Ru-containing material, Rh-containing material,and Os-containing material is between the two spaced magnetic regions.The at least one of Ir-containing material, Ru-containing material,Rh-containing material, and Os-containing material is directly againstthe 7 Angstroms thick magnetic Co_(g)Fe_(h)B_(i). The other magneticregion comprises 14 Angstroms thick elemental Co directly against the atleast one of Ir-containing material, Ru-containing material,Rh-containing material, and Os-containing material. At least one ofnon-magnetic elemental Ir, non-magnetic elemental Pt, and non-magneticelemental Ru is directly against the 14 Angstroms thick elemental Co.Non-magnetic Ni_(s)Fe_(t)Cr_(u) is directly against the at least one ofnon-magnetic elemental Ir, non-magnetic elemental Pt, and non-magneticelemental Ru, where “s” is from 50 to 100, “t” is from 0 to 30, and “u”is from 0 to 45. The at least one of non-magnetic elemental Ir,non-magnetic elemental Pt, and non-magnetic elemental Ru is beingbetween the magnetic Co-containing material and the non-magneticNi_(s)Fe_(t)Cr_(u).

In some embodiments, a magnetic tunnel junction comprises a conductivefirst magnetic electrode comprising magnetic recording material, aconductive second magnetic electrode spaced from the first electrode andcomprising magnetic reference material, and a non-magnetic tunnelinsulator material between the first and second electrodes. The magneticreference material of the second electrode comprises a syntheticantiferromagnetic construction comprising two spaced magnetic regionsone of which is closer to the tunnel insulator material than is theother. The one magnetic region comprises a polarizer region comprisingCo_(x)Fe_(y)B_(z) where “x” is from 0 to 90, “y” is from 10 to 90, and“z” is from 10 to 50. The Co_(x)Fe_(y)B_(z) is directly against thetunnel insulator. A non-magnetic region comprising an Os-containingmaterial is between the two spaced magnetic regions. The other magneticregion comprises a magnetic Co-containing material.

In some embodiments, a magnetic tunnel junction comprises a conductivefirst magnetic electrode comprising magnetic recording material. Aconductive second magnetic electrode spaced from the first electrode andcomprising magnetic reference material. A non-magnetic tunnel insulatormaterial is between the first and second electrodes. The first magneticelectrode comprises dielectric material. The magnetic recording materialis between the dielectric material and the tunnel insulator. The firstmagnetic electrode comprises non-magnetic conductive material. Thedielectric material is between the non-magnetic conductive material andthe magnetic recording material. The first magnetic electrode is devoidof any magnetic polarizer region between the dielectric material and thenon-magnetic conductive material. The magnetic reference material of thesecond electrode comprises a synthetic antiferromagnetic constructioncomprising two spaced magnetic regions one of which is closer to thetunnel insulator material than is the other. The one magnetic regioncomprises a polarizer region comprising Co_(x)Ye_(y)B_(z) where “x” isfrom 0 to 90, “y” is from 10 to 90, and “z” is from 10 to 50. TheCo_(x)Ye_(y)B_(z) is directly against the tunnel insulator. Anon-magnetic region comprising an Os-containing material is between thetwo spaced magnetic regions. The Os-containing material is directlyagainst the Co_(x)Ye_(y)B_(z). The other spaced magnetic regioncomprises magnetic Co-containing material directly against theOs-containing material. Non-magnetic Ni_(s)Fe_(t)Cr_(u) is directlyagainst the magnetic Co-containing material, where “s” is from 50 to100, “t” is from 0 to 30, and “u” is from 0 to 45. The Co-containingmaterial is between the Os-containing material and the non-magneticNi_(s)Fe_(t)Cr_(u).

In compliance with the statute, the subject matter disclosed herein hasbeen described in language more or less specific as to structural andmethodical features. It is to be understood, however, that the claimsare not limited to the specific features shown and described, since themeans herein disclosed comprise example embodiments. The claims are thusto be afforded full scope as literally worded, and to be appropriatelyinterpreted in accordance with the doctrine of equivalents.

The invention claimed is:
 1. A magnetic tunnel junction comprising: aconductive first magnetic electrode comprising magnetic recordingmaterial; a conductive second magnetic electrode spaced from the firstelectrode and comprising magnetic reference material; a non-magnetictunnel insulator material between the first and second electrodes; andthe magnetic reference material of the second electrode comprising asynthetic antiferromagnetic construction comprising: two spaced magneticregions one of which is closer to the tunnel insulator material than isthe other, the one magnetic region comprising: a polarizer regioncomprising Co_(x)Fe_(y)B_(z) where “x” is from 0 to 90, “y” is from 10to 90, and “z” is from 10 to 50; the Co_(x)Fe_(y)B_(z) being directlyagainst the tunnel insulator; at least one of elemental W, elemental Mo,elemental Fe, Co_(a)Fe_(b)W_(c), Co_(a)Fe_(b)Mo_(c), andCo_(a)Fe_(b)Ta_(c) directly against the Co_(x)Fe_(y)B_(z), where “a” isfrom 0 to 50, “b” is from 50 to 99, and “c” is from 1 to 50; andmagnetic Co_(g)Fe_(h)B_(i) directly against the at least one ofelemental W, elemental Mo, elemental Fe, Co_(a)Fe_(b)W_(c),Co_(a)Fe_(b)Mo_(c), and Co_(a)Fe_(b)Ta_(c), where “g” is from 0 to 100,“h” is from 0 to 90, and “i” is from 0 to 50, with at least one of “g”and “h” being greater than zero; a non-magnetic region comprising atleast one of Ir-containing material, Ru-containing material,Rh-containing material, and Os-containing material between the twospaced magnetic regions; and the other magnetic region comprising amagnetic Co-containing material directly against the at least one ofIr-containing material, Ru-containing material, Rh-containing material,and Os-containing material.
 2. The magnetic tunnel junction of claim 1comprising at least one of non-magnetic elemental Ir, non-magneticelemental Pt, and non-magnetic elemental Ru directly against themagnetic Co-containing material; the Co-containing material beingbetween a) the at least one of Ir-containing material, Ru-containingmaterial, Rh-containing material, and Os-containing material and b) theat least one of nonmagnetic elemental Ir, non-magnetic elemental Pt, andnon-magnetic elemental Ru.
 3. The magnetic tunnel junction of claim 2comprising non-magnetic Ni_(s)Fe_(t)Cr_(u) directly against the at leastone of non-magnetic elemental Ir, non-magnetic elemental Pt, andnon-magnetic elemental Ru, where “s” is from 50 to 100, “t” is from 0 to30, and “u” is from 0 to 45; the at least one of non-magnetic elementalIr, non-magnetic elemental Pt, and non-magnetic elemental Ru beingbetween the magnetic Co-containing material and the non-magneticNi_(s)Fe_(t)Cr_(u).
 4. The magnetic tunnel junction of claim 1 whereinthe first magnetic electrode comprises dielectric material, the magneticrecording material being between the dielectric material and the tunnelinsulator, the first magnetic electrode comprising non-magneticconductive material, the dielectric material being between thenon-magnetic conductive material and the magnetic recording material,the first magnetic electrode being devoid of any magnetic polarizerregion between the dielectric material and the non-magnetic conductivematerial.
 5. The magnetic tunnel junction of claim 4 wherein thedielectric material and the tunnel insulator are the same composition.6. The magnetic tunnel junction of claim 5 wherein the composition isMgO.
 7. The magnetic tunnel junction of claim 4 wherein the dielectricmaterial has a smaller thickness than that of the tunnel insulator. 8.The magnetic tunnel junction of claim 1 wherein “x” is zero.
 9. Themagnetic tunnel junction of claim 1 wherein “x” is greater than zero.10. The magnetic tunnel junction of claim 1 wherein the “a” is zero andthe at least one of elemental W, elemental Mo, elemental Fe,Co_(a)Fe_(b)W_(c), Co_(a)Fe_(b)Mo_(c), and Co_(a)Fe_(b)Ta_(c) comprisesat least one of Fe_(b)W_(c), Fe_(b)Mo_(c), and Fe_(b)Ta_(c).
 11. Themagnetic tunnel junction of claim 1 wherein the at least one ofelemental W, elemental Mo, elemental Fe, Co_(a)Fe_(b)W_(c),Co_(a)Fe_(b)Mo_(c), and Co_(a)Fe_(b)Ta_(c) comprises at least one ofCo_(a)Fe_(b)W_(c), Co_(a)Fe_(b)Mo_(c), and Co_(a)Fe_(b)Ta_(c) where “a”is greater than zero.
 12. The magnetic tunnel junction of claim 1wherein the at least one of elemental W, elemental Mo, elemental Fe,Co_(a)Fe_(b)W_(c), Co_(a)Fe_(b)Mo_(c), and Co_(a)Fe_(b)Ta_(c) compriseselemental W.
 13. The magnetic tunnel junction of claim 1 wherein the atleast one of elemental W, elemental Mo, elemental Fe, Co_(a)Fe_(b)W_(c),Co_(a)Fe_(b)Mo_(c), and Co_(a)Fe_(b)Ta_(c) comprises elemental Mo. 14.The magnetic tunnel junction of claim 1 wherein the at least one ofelemental W, elemental Mo, elemental Fe, Co_(a)Fe_(b)W_(c),Co_(a)Fe_(b)Mo_(c), and Co_(a)Fe_(b)Ta_(c) comprises elemental Fe. 15.The magnetic tunnel junction of claim 1 wherein the at least one ofelemental W, elemental Mo, elemental Fe, Co_(a)Fe_(b)W_(c),Co_(a)Fe_(b)Mo_(c), and Co_(a)Fe_(b)Ta_(c) comprises Co_(a)Fe_(b)W_(c)where “a” is greater than zero.
 16. The magnetic tunnel junction ofclaim 1 wherein the at least one of elemental W, elemental Mo, elementalFe, Co_(a)Fe_(b)W_(c), Co_(a)Fe_(b)Mo_(c), and Co_(a)Fe_(b)Ta_(c)comprises Co_(a)Fe_(b)Mo_(c) where “a” is greater than zero.
 17. Themagnetic tunnel junction of claim 1 wherein the at least one ofelemental W, elemental Mo, elemental Fe, Co_(a)Fe_(b)W_(c),Co_(a)Fe_(b)Mo_(c), and Co_(a)Fe_(b)Ta_(c) comprises Co_(a)Fe_(b)Ta_(c)where “a” is greater than zero.
 18. The magnetic tunnel junction ofclaim 1 wherein the at least one of elemental W, elemental Mo, elementalFe, Co_(a)Fe_(b)W_(c), Co_(a)Fe_(b)Mo_(c), and Co_(a)Fe_(b)Ta_(c)comprises a mixture or alloy of at least two of elemental W, elementalMo, elemental Fe, Co_(a)Fe_(b)W_(c), Co_(a)Fe_(b)Mo_(c), andCo_(a)Fe_(b)Ta_(c).
 19. The magnetic tunnel junction of claim 18 whereinthe at least one of elemental W, elemental Mo, elemental Fe,Co_(a)Fe_(b)W_(c), Co_(a)Fe_(b)Mo_(c), and Co_(a)Fe_(b)Ta_(c) comprisesa mixture or alloy of at least three of elemental W, elemental Mo,elemental Fe, Co_(a)Fe_(b)W_(c), Co_(a)Fe_(b)Mo_(c), andCo_(a)Fe_(b)Ta_(c).
 20. The magnetic tunnel junction of claim 1 whereinthe at least one of Ir-containing material, Ru-containing material,Rh-containing material, and Os-containing material comprises a mixtureor alloy of at least two of elemental Ir, elemental Ru, elemental Rh,and elemental Os.
 21. The magnetic tunnel junction of claim 20 whereinthe at least one of Ir-containing material, Ru-containing material,Rh-containing material, and Os-containing material comprises a mixtureor alloy of at least three of elemental Ir, elemental Ru, elemental Rh,and elemental Os.
 22. A magnetic tunnel junction comprising: aconductive first magnetic electrode comprising magnetic recordingmaterial comprising 3 Angstroms thick Fe directly against an alloycomprising Co, Fe, and B that is 10 Angstroms thick; a conductive secondmagnetic electrode spaced from the first electrode and comprisingmagnetic reference material; a non-magnetic tunnel insulator materialbetween the first and second electrodes; and the first magneticelectrode comprising dielectric material directly against the Fe; thealloy comprising Co, Fe, and B being directly against the tunnelinsulator, the first magnetic electrode comprising non-magneticconductive material directly against the dielectric material, the firstmagnetic electrode being devoid of any magnetic polarizer region betweenthe dielectric material and the non-magnetic conductive material; themagnetic reference material of the second electrode comprising asynthetic antiferromagnetic construction comprising: two spaced magneticregions one of which is closer to the tunnel insulator material than isthe other, the one magnetic region comprising: a 7 Angstroms thickpolarizer region comprising Co_(x)Fe_(y)B_(z) where “x” is from 0 to 90,“y” is from 10 to 90, and “z” is from 10 to 50; the Co_(x)Fe_(y)B_(z)being directly against the tunnel insulator; a 2 Angstroms thick regionof at least one of elemental W, elemental Mo, elemental Fe,Co_(a)Fe_(b)W_(c), Co_(a)Fe_(b)Mo_(c), and Co_(a)Fe_(b)Ta_(c) directlyagainst the Co_(x)Fe_(y)B_(z), where “a” is from 0 to 50, “b” is from 50to 99, and “c” is from 1 to 50; and 7 Angstroms of magneticCo_(g)Fe_(h)B_(i) directly against the at least one of elemental W,elemental Mo, elemental Fe, Co_(a)Fe_(b)W_(c), Co_(a)Fe_(b)Mo_(c), andCo_(a)Fe_(b)Ta_(c), where “g” is from 0 to 100, “h” is from 0 to 90, and“i” is from 0 to 50 with at least one of “g” and “h” being greater thanzero; a 7 Angstroms thick non-magnetic region comprising at least one ofIr-containing material, Ru-containing material, Rh-containing material,and Os-containing material between the two spaced magnetic regions; theat least one of Ir-containing material, Ru-containing material,Rh-containing material, and Os-containing material being directlyagainst the 7 Angstroms thick magnetic Co_(g)Fe_(h)B_(i); and the othermagnetic region comprising 14 Angstroms thick elemental Co directlyagainst the at least one of Ir-containing material, Ru-containingmaterial, Rh-containing material, and Os-containing material; at leastone of non-magnetic elemental Ir, non-magnetic elemental Pt, andnon-magnetic elemental Ru directly against the 14 Angstroms thickelemental Co; and non-magnetic Ni_(s)Fe_(t)Cr_(u) directly against theat least one of non-magnetic elemental Ir, non-magnetic elemental Pt,and non-magnetic elemental Ru, where “s” is from 50 to 100, “t” is from0 to 30, and “u” is from 0 to 45; the at least one of non-magneticelemental Ir, non-magnetic elemental Pt, and non-magnetic elemental Rubeing between the magnetic Co-containing material and the non-magneticNi_(s)Fe_(t)Cr_(u).
 23. The method magnetic tunnel junction of claim 22wherein the non-magnetic Ni_(s)Fe_(t)Cr_(u) is 30 Angstroms thick. 24.The magnetic tunnel junction of claim 1 wherein the Co-containingmaterial is elemental Co.